"No, the GPS will not go down," said Col. Dave Buckman, command lead for position, navigation and timing at the Peterson Air Force Space Command in Colorado. However, citing an earlier report by the Government Accountability Office, the investigative arm of Congress, Buckman added, "GAO points out, there is potential risk associated with a degradation in GPS performance."

Buckman commented during a one-hour session yesterday on the command's Twitter page. A appears on the command's Web site.

GPS, now comprised of 31 operational satellites, is a free service provided by the U.S. government. Nearly $6 billion is alloted over the next five years to provision new GPS satellites and ground control facilities, according to government records.

Buckman is the command's subject matter expert on the GPS program, which has been under the stewardship of the U.S. Air Force and the command since its inception in the 1970s. A short statement on the command's site attempts to assure the public that the GPS system is secure.

"The current GPS constellation has the most satellites and the greatest capability ever," the statement says. "We are committed to maintaining at least our current level of service, while striving to improve service and capability through on-going modernizaton efforts. The Air Force will continue to pursue an achievable path maintaining GPS as the premier provider of positioning, navigation and timing for the military and civilian users around the world."